More Clintonian PolitiMath

With our PolitiMath posts we look for correlations between numerical errors and PolitiFact's "Truth-O-Meter" ratings. Today's item looks at PolitiFact's rating of Democratic presidential candidate Hillary Rodham Clinton, who said she is the only candidate with a specific plan to fight ISIS.

PolitiFact said there were at least seven such plans among presidential candidates and gave Clinton a "False" rating (bold emphasis added):

While Clinton’s plan is more detailed, by some measurements, than those of other candidates, at least seven other candidates in both parties have released multi-point plans for taking on ISIS. Some plans -- such as those from Bush and Rubio -- approach Clinton’s in either length or degree of detail. In fact, there’s a significant degree of overlap between the agenda items in Clinton’s plan and in plans released by other candidates.

We don’t see strong evidence for Clinton’s claim that she’s the only member of the 2016 field with a "specific plan." We rate the claim False.

Clinton, using PolitiFact's estimates as a basis, underestimated the number of specific plans for defeating ISIS by 86 percent.

We found a close parallel to this case involving Republican candidate Rick Santorum (an 83 percent underestimation). PolitiFact rated Santorum "False" also.